The present invention relates in general to image processing, and in particular to identifying relative z-values between segments found in an image and using the relative overlap information in digital image processing.
The solution disclosed herein is to determine the z-ordering information contained within a sequence of image frames that are temporally correlated. Z-ordering literally means to order by the “z”, or depth axis. In other words, z-ordering means sequencing, or ordering, the image regions based upon how deep within the image frame they are. In this convention, z-ordering is measured from the viewer's perspective. Therefore, the further away an image region, or the deeper it is within an image frame, the higher the z-value of that region.
Determining the z-order or depth of different regions of an image is very useful for applications such as digital image manipulations, image/video editing, video compression and various other digital image processing applications.
In general, knowing the z-order of different objects within an image allows the video frames to be edited or manipulated because it now becomes possible to remove or add objects to this sequence of image frames without the loss of image integrity or image quality. Currently no methods exist that can satisfactorily identify the z-order of arbitrary objects within a temporally correlated image sequence.
Z-ordering, as applied in this patent, represents an entirely new technology. There is currently no widely available technology that permits the determination of z-ordering information, from an arbitrarily chosen sequence of digital image frames, without human intervention. Current z-ordering routines are limited to the reverse application; i.e. drawing an image frame after the z-ordering is known. For example, in FIG. 1, there are three image regions to be drawn, a cloud, the sun, and the background regions 11 through 13 respectively. If the cloud has the z-ordering 1, the sun z-ordering 2, and the background, z-ordering 3, the image drawing routine knows to draw the background first, then the sun, and finally the cloud.